I went into Sunday night’s John C. Reilly & Friends show at the Miller Caves with no expectations at all. I’d never heard Reilly’s music before – unless you count "Boogie Nights" and "Walk Hard," but I’m a big fan of his work as an actor. I’d never seen a show in the Miller Caves (and nor had anyone else) but I remember being impressed with the space on brewery tours in the past.

Still, no matter how high I could’ve set the bar for this unique folk/bluegrass/Americana/country show in an even more unique venue, this show would’ve surpassed it. This is the kind of concert I’ll never forget.

First, a few words about the tiny venue. Capacity is only 100 in the cool, dank cave. The stage was set at one end, in front of an old mural, presumably depicting Fredrick Miller’s childhood. Because it’s so small, everyone was impossibly close to the musicians; the musicians barely needed to be mic’ed, and they heard everything the audience said. It smelled a little funky. After two hours standing on hard stone, my feet hurt. Because the stage wasn’t really raised, if was a tall person in front (and there was), you might not have had a great view.

And it was amazing.

Buffeting this spectacular room, if you can call it that, was Reilly and his band. Lest you think this is a movie star playing musician, think again. Yes, Reilly surrounded himself with top-notch folk musicians, guitars, banjos, stand-up bass and beautiful vocalists, but he’s no slouch at all.

The band played dusty old gems that spanned numerous genres, from folk to bluegrass to country to Americana. They invoked tunes from The Carter Family, George Jones and Woody Guthrie; every song had a certain genuine sweetness to it, and while I can’t relate names of the songs since I’d never heard any of them before, each left the enthralled crowd smiling and clapping along.

Two of the singers, the goofy, adorable Becky Stark and the lanky, high-pitched Tom Brosseau, clearly had outstanding talent, while the rest – Reilly included – sang with so much passion that their vocal quality was elevated from good to great. The musicianship, however, was top-notch, and with beautiful harmonies and tight rhythms (no drums here), the rotating ensemble made enchanting music in the second of two shows Sunday night. Iowa’s Dan Bern on guitar was also a nice treat.

In a way, between the excellent opening one-man act, and this group, it felt a little like listening to "A Prairie Home Companion," but that’s perhaps unfair. I actually can’t stand that show, and this was as good as good can be.

Of course, Reilly brought along his self-deprecating sense of humor. He called the cheesy pre-show Miller hologram "creepy," and joked about his lack of lead guitar skills. He thanked the "slaves" for building the cave, and promised next time, he’d play at a larger cave in Milwaukee.

Reilly, wearing a vest and an old-timey hat, pointed out that the audience came for his name, but his goal was to shed light on this amazing group of singer-songwriters. Reilly also poked fun at Milwaukee’s drinking culture (he’s from Chicago) and slipped when he referred to Miller as the King of Beers – but only a few of us realized that tiny mistake.

In the end, this $30 show – which included three Miller craft beers – excelled in every possible way, setting the stage for future special shows in the Caves. Given the size restrictions, I’m not sure who The Pabst Theater can book in this venue, but if Reilly and friends was typical of what Milwaukee concert goers can expect, this cave is really a gold mine.